Cord forming



Juhe 18, 1957 J, PARKER 5 AL 2,795,925

CORD FORMING Filed June 26, 1953 2 Sheets-Sheet 1 1 Fig.1.

I N VEN TORS Jdines P. Parker .ErnestJ. GrisenJr.

ATTORNEY Jung 18, 1957 Filed June 2 6, 1955 J. P. PARKER El AL CORD FORMING 2 Sheets-Shee t 2 INVENToRS Jams P. Parker Fr'nest l Grise t, J1:

ATTORNEY United States Patent 9 i CORD FORMING .lames P. Parker and Ernest J. Griset, Jr., Asheville, N. C., assignors to American Enka Corporation, Enka, N. C., a corporation of Delaware Application June 26, 1953, Serial No. 364,322

1 Claim. (Cl. 57-106) This invention relates to the production of a plied structure and more particularly to the production of a cord formed on a ring twister. a

Ring twisters are widely used in the production of strands or cords. In this process two or more yarns called singles are pulled from supply packages by feed rolls, passed through a guide and then to a traveler, after which the plied structure is taken up on a rotating bobbin. The speed of the bobbin and other characteristics of the ring twister determine the nature and extent of the twist imparted to the plied structure.

Large quantities of high tenacity cord are produced by the foregoing process for use in the manufacture of fabric for reinforcing rubber articles such as tires. In the production of such tire cord it is customary to use high twist singles, i. e., singles which have been previously twisted themselves, and to twist the pretwisted singles in the reverse direction into a twisted cord having strength and fatigue properties far superior to those in the singles.

It is an object of the present invention to provide an improved method and apparatus for producing cord.

A further object of the invention is to provide a method for producing tire cord having superior properties.

A still further object of the invention is to provide an improved ring twisting apparatus for the manufacture of cords.

Other objects of the invention will appear from the description given hereinafter when considered in conjunction with the attached drawings wherein:

Figure 1 is a view in front elevation of a preferred form of an apparatus for practicing the present invention;

Figure 2 is a view in section taken along the lines 22 in Figure 1;

Figure 3 is a perspective view of an improved type thread guide used in practicing the present invention;

Figure 4 is a perspective view of a modified type thread guide used in practicing the present invention; and

Figure 5 is a plan view of a ring twister showing another embodiment of the invention.

In accordance with the present invention cord having superior physical characteristics may be formed on a ring twister by carefully controlling the point at which the plying takes place. In a preferred form of the invention the point of plying is controlled by inserting a separating element in the thread path between the feed rolls and the traveler of the ring twister. In this way the point of plying is maintained between the element and the traveler and not permitted to back up into contact with the feed rolls.

In conventional ring twisters for producing cord the twist is inserted as the singles emerge from the feed roll assembly where the point of plying is somewhat confined by these rolls. It has been found that the cord produced in this manner is not consistantly uniform in strength and other physical properties.

In an effort to improve the physical properties of cord made on ring twisters it has been found that if the singles 2,195,925 Patented June 18, 1957 ice are kept separate until they are completely free of the feed rolls and then allowed to combine in free space, the resulting cord geometry is more regular and compact. These characteristics have been found to be associated in general with cords having higher strength and better fatigue properties.

Referring now to Figures 1 and 2, twisted singles 12 and 13 which are to be twisted together to form twisted cord 14 are withdrawn fromsupply packages (not shown), The singles 12 and 13 are withdrawn from their supply packages by means of driven feed rolls 15, 16 and freely rotatable cradle roll 17. Upon emerging from the feed rolls the singles are passed through a guide 18 and then through traveler 19 running on ring 20 and taken up by a rotating bobbin 21 driven by suitable means (not shown).

In accordance with the present invention there is interposed between the feed rolls and the guide 18 a cylindrical bar 22. The axis of bar 22 is normal to the axis of the feed rolls. As shown in Figures 1 and 3 the bar 22 may optionally be combined with the thread guide 18 in a unitary structure The singles passing from the feed roll are passed around the opposite sides of the cylindrical bar 22 as shown in Figure 1, thus preventing any possibility of the plied structure 14 being formed adjacent to or in contact with the feed roll assembly.

Inoperation, the point of plying is maintained at a distance of about inch below the surface of cylindrical bar 22. It is believed that the superior results obtained with the present invention are due to the fact that the singles are allowedto combine below cylindrical bar 22 in free space and are thus not subjected to undue flucrtuation caused by moving parts.

Figure 2 illustrates more clearly the path of thread travel from the supply packages to the ring twister bobbin 21. It will be noted that the singles are passed underneath the first driven feed roll 15, then between feed roll 15 and cradle roll 17 'and from there between driven feed roll 16 and cradle roll 17. The unitary structure comprising the separating guide 22 and pigtail guide 18 is mounted on a horizontal rail 23 running the length of the ring twisting machine by means of threaded portion 24. It will be apparent that the manner of mounting these elements is not a critical part of the invention and they may be affixed to the ring twister apparatus in any appropriate way.

Figure 3 shows a perspective view of the unitary structure comprising the separating guide 22 and the pigtail guide 18.

A modified form of separating guide is shown in Figure 4. A small wheel 25 is mounted in freely rotatable relation on axle 26. Wheel 25, which may be constructed of plastic or other suitable material, is provided with a grooved portion 27 around its periphery to accommodate the running singles. To utilize this form of the invention one single is passed around one side of the wheel 25 and one single around the opposite side. The point of plying then is located below the wheel 25.

Another embodiment of the present invention is shown in Figure 5. In this embodiment the point at which the singles are twisted together to form the plied structure is controlled by means of thread guides interposed between the supply packages and the feed rolls. Singles 28 and 29 are withdrawn from supply packages (not shown) and passed through thread guides 30 and 31, respectively. Guides 30 and 31 are spaced far enough apart so that the singles 28 and 29 will be maintained in spaced relation during their passage through the assembly of feed rolls and cradle roll 1517. It is seen that the point of plying 32 occurs in free space a short distance from the feed roll assembly. The plied structure is then led via guide 33 to the ring twister takeup as usual. The optimum distance between guides 30 and 31 will, of course, depend on the size and the weight of the feed rolls and cradle roll, as well as the type of twist in the singles and the final cord.

The effect of varying the distance between thread guides 30 and 31 in Figure 5 was determined as follows. Singles of 1650 denier viscose high tenacity rayon containing 720 filaments and having 12 T. P. I. Z twist were withdrawn from supply packages by a feed roll assembly similar to that shown in Figure 5 and taken up on a ring twister operating to put 12 T. P. I. S twist in the plied cord. Before passing through the feed roll assembly the singles were passed through spaced thread guides 30 and 31. A number of samples were run with the same singles, varying the spacing between the thread gulides. Results obtained are given in Table I below. Conditioned strengths given in Table I are cord strengths.

Table 1 Good. strength Distance between guides, mm: grm./ 100 den.

Junction point of singles fell into contact with surface of both feed roll and cradle roll until distance between guides was at least 3 mm.

8 Junction point of singles fell on surface of feed roll only until distance between guides was at least 12 mm.

The data given in Table I illustrates the increase in cord strength obtained by maintaining the point of cord formation either out of contact with the cradle roll or preferably in free space and completely out of contact with any part of the feed roll assembly. This data, of course, is of qualitative nature since the distances and strengths would be expected to vary from one type thread to another and from one type cord twist constructed to another.

The eifect of varying the diameter of the cylindrical bar 22 shown in Figures 1, 2 and 3 was determined as follows. Singles of 1650 denier viscose high tenacity rayon containing 720 filaments and having 12 T. P. I. 2" twist were withdrawn from supply packages by a feed roll assembly similar to that shown in Figures 1 and 2 and taken up on a ring twister operating to put 12 T. P. I. S twist in the plied cord. After passing through the feed roll assembly the singles were conducted around opposite sides of a separator bar 22 before passing through thread guide 18 as shown in Figure 1. A number of samples were run withthe same singles, using bars 22 with varying diameters. The effect on cord strength may be seen in Table II. This data indicates that the size of the separator bar is not critical.

Table II It will be apparent from the foregoing that other modifications may be made within the spirit of this invention and-it is desired to include such modifications or variations within the scope of the appended claim.

What is claimed is:

An apparatus for producing a cord from two single threads comprising an assembly of iced rolls for feeding the singles at a uniform rate of speed in side by side relation, a ring twister spindle including a bobbin for twisting the singles together and for collecting the twisted cord and a unitary elongated cylindrical bar separator and pigtail-type guide disposed in the path of thread travel between said assembly of feed rolls and said ring twister spindle, said guide being mounted integral with and disposed beneath said separator, said separator being disposed in a substantially horizontal plane with the longitudinal axis thereof extending normal to the direction of travel of the cord through the pigtail-type guide.

References Cited in the file of this patent UNITED STATES PATENTS 1,134,315 Coldwell Apr. 6, 1915 2,061,498 Bird ,Nov. 17, 1936 2,309,095 Bry Jan. 26, 1943 FOREIGN PATENTS,

287,702. Germany Oct. 3, 1915 376,512 Great Britain July 14, 1932 

